Connecting plate assembly for plate heat exchangers



April 26, 1960 R. P. L..HYTTE 2,934,321

CONNECTING PLATE ASSEMBLY FOR PLATE HEAT EXCHANGERS Filed May 31, 1955 asheets-sheet 1 //VVENmR obs/ yonfus [amen Zia fie ATTORNEYS April 26,1960 LATE ASSEMBLY FOR PLATE HEAT EXCHANGERS TORNEYS April 26, .1960 R.P. L. HYTTE CONNECTING PLATE ASSEMBLY FOR PLATE HEATEXCHANGERS 3Sheets-Sheet 3 Filid lay 31, 1955 uhl hhnnnhmw Q CONNECTING PLATEASSEMBLY FOR PLATE HEAT EXCHANGERS Robert Pontus Larsson Hytte,Ljungbusen, Sweden, as-

signor to Aktiebolaget Separator, Stockholm, Sweden, a corporation ofSweden This invention relates to plate heat exchangers and particularlyto an improved connecting plate assembly by which fluids can be fed toor withdrawn from the spaces within the pack of plates.

Plate heat exchangers, such as those used for treatment of milk and milkproducts, wort, beer and other liquids, comprise a plurality of similarheat exchange plates assembled into a pack. It is often desired tosupply fluid to or withdraw it from the spaces between the plates at acertain point in the plate pack, this fluid being either the liquidunder treatment in the apparatus or a fluid for the treatment of theliquid, such as steam for heating the liquid or water for cooling theliquid. In many instances it is desired to withdraw the liquid from themiddle of the plate pack for purposes of filtration, separation, or thelike, and to return the liquid thus treated to the same place in theplate pack and to the same corner of the heat exchanging plates fromwhich it was withdrawn.

To effect this supply and/or withdrawal of fiuid, it is common practiceto insert a connecting plate at the desired place in the plate pack, theconnecting plate dividing the plate pack into separate sections. Thisconnecting plate is provided with one or more pipe connections forcarrying the liquid or the other fluid into and/ or out of the platepack, such pipe connections being located opposite the usual passageholes in the heat-exchange plates. As the latter plates usually arerectangular and the passage holes are located in the corner portions ofthese plates, the pipe connections of the connecting plates are locatedin the corner portions of the connecting plates. It is not alwaysnecessary, however, that liquid be led in and out at each corner of theconnecting plate. Often the liquid is merely passed through theconnecting plate to the adjoining plate section, in which case the pipeconnections are replaced by a simple pipe.

A connecting plate which is not passed or contacted by the treatedliquid or by other fluids may be made of a simple and cheap material,such as cast iron. However, the pipe connections which are passed andtherefore contacted by these liquids and by corrosive detergents (whenthe apparatus is cleaned by means of strong chemicals) must be made ofvery corrosion-resistant material, as in the case of the heat-exchangeplates themselves. It has long been the practice, therefore, to use onlyhigh-grade stainless steel for these details.

As these pipe connections in the connecting plates must be of a rathercomplicated form, they have heretofore been made of cast material which,as previously indicated, is of the stainless type. Such cast cornershave the drawback, however, that there often are pores in the casting,and these pores after an initial working must usually be welded in orderthat the pipe connection may be tight, or to avoid dirt crannies adbacteria colonies. This repairing is an expensive and troublesomeoperation which often results in the pipe connection being finallydiscarded as impossible to repair, after much expensive work has alreadybeen performed in efforts to remedy the flaws in the casting.

ted States Patent C i 2,934,321 Patented Apr. 26, 1960 "ice The presentinvention has for its principal object the remedying of these defectsand the provision of an improved connecting plate assembly in whichgrowth of the bacterial culture in the pipe connections is prevented.The pipe connections according to the present invention are in the formof easily exchangeable and detachable units in order to facilitatecleaning and inspection and so as to prevent formation of bacteriacolonies in the pipe connections, because such colonies impair thequality of the medium flowing through the plate apparatus.

The invention is illustrated in the accompanying drawings, in which:

Fig. I is a face view of a preferred form of the new connecting plate,showing its pipe connections;

Fig. II is an enlarged sectional view of a corner portion of theconnecting plate, showing means whereby the connecting pipe can beattached to the plate through the pipe connection in various angularpositions; 1

Fig. III is a sectional view on line III-III in Fig. II;

Figs. IV and V are sectional views of modified forms of the pipeconnection, and

Fig. VI is an end view of still another form of the pipe connection.

Referring to Fig. I, the connecting plate 1 is adapted to be insertedbetween a pair of plates in a plate heat exchanger, as will be readilyunderstood by those skilled in the art. At its corners, the plate 1 isprovided with connecting pipe units 2 each of which is held by areleasable device or screw 3 in a semi-circular or arcuate seat 4 of theplate. Each connecting unit 2 comprises a' pipe 5 which fits into thearcuate corner recess formed by a seat 4 of the plate, the axis of pipe5 being normal to the plane of plate 1. The connecting unit 2 has one ormore connecting pipes 6, 7 secured to pipe 5. The latter has at leastone threaded hole 8 extending only partly through the pipe wall. Asshown in Fig. 2, there are two such holes 8 and 12 displaced at an anglefrom each other (e.g., on the connecting pipe 5. The screw 3 of eachunit 2 extends through a hole in the seat 4 and is screwed into thethreaded hole 8 or 12 of the pipe 5. The screws 3 are arranged at asuitable angle (e.g. 45 in relation to the side edges of the connectingplate '1'. By placing the screws 3 at an angle of 45 tothese side edgesof the connecting plate and providing each pipe '5 ,with two threadedholes 3 and 12 at an angle of 90 in relation to each other, then thepipe connection 5 may be easily loosened, turned through 90 andtightened again by means of screw 3, so that the out-going pipe 6 or 7is changed from a horizontal to a vertical position or vice versa,depending upon which position is better suited to the mounting of acertain pipe line. (Compare the connections to the right and to the leftat the top of Fig. 1.)

To provide for a plurality of pipe connections, each connecting unit 2comprises at least three pipes (Figs. I, IV, V and VI), one of which isthe pipe 5 and the others including the two side pipes 6, 7. These threepipes are joined so as to form a corner unit of the plate 1. The threepipes 5, 6 and 7 preferably form a 90 angle in relation to each other,the two branch pipes or side con'- nections 6 and 7 both being betweenthe planes of the two opposite faces of connecting plate 1 and formingtwo separate liquid paths. Thus, the liquid flow to or from the platepack adjacent one face of plate 1 is led through one side pipe 6, andthe liquid flow to or from the plate pack adjacent the other face ofplate 1 is led through the other side pipe 7.

The simplest way of joining the pipe parts 5-6 or 5-67, to form aconnecting unit 2, is no doubt to weld them together. However, pores ordeformations are often formed through thermal stress caused by thewelding. According to the present invention, therefore, this welding isreplaced by rolling in the side connections 6-7 in the flow pipe (seeFigs. II-VT). It is true that in this case the pipe 5 must beconstructed with a thicker wall than would otherwise be necessary, butthe troublesome welding is avoided. By turning a groove 9 around thehole for receiving each pipe 67, the latter is secured from looseningafter it has been rolled into the side hole in pipe 5.

By rolling in the side connections as described, a bad dirt cranny couldbe formed at their inner ends. To avoid this, each bored hole in thepipe 5 for the side-connection is provided with a stop extending allaround the side pipe 6 or 7 and being approximately as deep as thematerial thickness of the side pipe. When rolling in the pipe 6 or 7,the inner end of this pipe is pressed hard against the stop 10 so thatthe joint between them is entirely closed and compressed, whereby theinner surface of the pipe connection is quite free from open .joints anddirt crannies. If desired, the junction of stop 10 and pipe 6 or 7 canbe subsequently pressed through an additional rolling operation, wherebyany risk of traces of the joint being left is avoided.

It is necessary, of course, to divide the two liquid flows in a pipeconnection unit 2 having two side pipes 6-7, that is, in a so-calleddouble connection. This can be done by pressing into the flow pipe 5 adisc-shaped partition 11, which preferably is fitted tightly in the pipe.and seated firmly against an internal shoulder 13 between the holes forthe side pipes 6 and 7 (Fig. IV), so that leakage is prevented. Thispartition can also be secured by welding it in the double-connectionpipe 5, whereby any risk of mixing the liquids is avoided. In the lattercase, the partition may be placed in an inclined position in relation tothe pipe 5 as well as to the two outgoing pipes 6-7. Alternatively, the.partition may be S- shaped, as shown at 110 in Fig. V, or Z-shaped asshown at 11b in Fig. VI, whereby the welding to secure the partition andany possible after-finishing of the weld joint are facilitated. At thesame time the thickness of the conecting plate 1 can be reduced by thesealternatives, because the two out-going pipes 67 may then be arrangedwith their axes in a common plane normal to and bisecting the axis ofpipe 5a (Figs. V and VI). Otherwise, the pipes 6-7 must bedisplaced'frorn each other in the axial direction of pipe 5 (Fig. IV).

In case the pipe connections 6 and 7 are replaced by a simple fiow pipeaffording only one passage (Fig. I), such pipe may be mounted andsecured in the connecting plate '1 in the same way as the multiple pipeconnections. In any case, each unit 2 includes a pipe 5 extendinggenerally perpendicular to the plane of the connecting plate 1 andhaving a flow passage affording communication to a heat exchange plateadjacent at least one face of the connecting plate.

The invention is not limited to the embodiment described herein. Forexample, the recesses formed by the seats 4 for receiving the connectingunits 2 at the plate corners may be shaped differently than as shown,the

connecting units being formed to fit these recesses.

The rolling in or rolling operation for joining the pipe parts 6 and '7to the pipe 5 takes place in such a way that the pipe 6 or 7, which fromthe beginning has a some what smaller diameter than has thecorresponding side hole in the pipe 5, is inserted in this side hole,whereupon a press roller is inserted in the pipe .6 and 7, respectively,and is forced during rolling to press the material of the pipe 6 and 7,respectively, against the wall of the side holes in the pipe 5. As aconsequence of this rolling operation, the thickness of material in thepipe 6 and 7, respectively, decreases, while the outer diameter of thepipe 6 and 7, respectively, increases so that the pipe 6 and 7,respectively, is 'at last completely secured to the pipe 5. Such rollingoperations for fixing a pipe in the hole of a member is well known inthe art and does not require any further explanation.

I claim:

1. For insertion in the pack of plates in a plate heat exchanger, toprovide a flow connection with the pack, the combination of a connectingplate having at least one corner portion provided with a peripheralrecess, said recess defining a seat in the form of a segment of a cylinder opening laterally toward said corner and extending throughout thethickness of the connecting plate, the axis of said cylinder beingnormal to the plane of the connecting plate, a pipe connecting unitincluding a pipe for said flow extending generally perpendicular to theplane of the connecting plate and having a cylindrical surface adaptedto fit against said cylindrical segment formed by the seat, said pipebeing movable into the recess at a right angle to said axis and beingadjustable about the pipe axis to different angular positions relativeto said seat, and releasable means for securing said pipe in the recessagainst said seat in a selected one of said angular positions.

2. The combination according to claim 1, in which said pipe includes athick-walled tubular part forming said cylindrical surface, said tubularpart having at least one side pipe extending at a right angle to theaxis of said thick-walled part.

3-. The combination according to claim 1, in which said pipe includes athick-walled tubular part forming said cylindrical surface, said tubularpart having at least one side pipe extending at a right angle to theaxis of said thick-walled part, said thick-walled tubular part beinglocated within the confines of an imaginary corner formed by extendingthe main side and end edges of the plate nearest said corner portionuntil said edges join each other.

4. The combination according to claim 1, in which said cylindricalsurface of the pipe has a plurality of threaded holes, said releasablemeans including a screw on the connecting plate insertable in a selectedone of said holes.

5. The combination according to claim 1, in which said releasable meansis a screw on the connecting plate, said plate having side edges and thescrew extending at an angle of approximately 45 to said side edges.

6. The combination according to claim 1, comprising also a side pipebranching from said first pipe of the connecting unit, the releasablemeans constituting a means for securing said first pipe in selectedangular positions on said seat and thereby varying the position of saidside pipe relative to the connecting plate.

7. The combination according to claim 1, comprising also a side pipebranching from said first pipe of the connecting unit, the releasablemeans being a screw on the connecting plate, said first pipe having apair of holes adapted to receive the screw and angularly displaced fromeach other around said first pipe, whereby the releasable means isoperable to secure the first pipe in selected angular positions on saidseat to vary the position of the side pipe relative to the connectingplate.

8. Thecombination according to claim 1, comprising also a pair of sidepipes branching from and communicating with the interior of said firstpipe of the connecting unit, and a partition positioned in said firstpipe to separate the points at which the side pipes communicate with theinterior of said first pipe.

9. The combination according to claim 1, comprising also a pair of sidepipes branching from and communicating with the interior of said firstpipe of the connecting unit, and a partition positioned in said firstpipe to separate the points at which the side pipes communicate with theinterior of said first pipe, said partition being welded in the firstpipe.

10. The combination according to claim 1, comprising also a pair of sidepipes branching from and communicating with the interior of said firstpipe of the connecting unit, and a partition positioned in said firstpipe to separate the points at which the side pipes communicate with theinterior of said first pipe, the partition being disc-shaped andpressed-tightly in said first pipe.

11. The combination according to claim 1, comprising also a pair of sidepipes branching from and communicating with the interior of said firstpipe of the connecting unit, and a partition positioned in said firstpipe to separate the points at which the side pipes communicate with theinterior of said first pipe, the partition extending at least partly atan angle to a plane normal to the axis of said first pipe.

12. The combination according to claim 1, comprising also a pair of sidepipes branching from and communicating with the interior of said firstpipe of the connecting unit, and a partition positioned in said firstpipe to separate the points at which the side pipes communicate with theinterior of said first pipe, the partition being generally S-shaped.

13. The combination according to claim 1, comprising also a pair of sidepipes branching from and communicating with the interior of said firstpipe of the connecting unit, and a partition positioned in said firstpipe to separate the points at which the side pipes communicate with theinterior of said first pipe, the partition being generally Z-shaped.

References (Jited in the file of this patent UNITED STATES PATENTS910,514 Dilts Ian. 26, 1909 1,174,288 Rosenfeld Mar. 7, 1916 1,368,770True Feb. 15, 1921 1,622,006 Seligrnan Mar. 22, 1927 2,252,274 Rossheimet a1 Aug. 12, 1941 2,551,393 Pinger May 1, 1951 2,654,352 SchoenfeldOct. 6, 1953 2,777,674 Wakeman Jan. 15, 1957 FOREIGN PATENTS 25,001Great Britain Oct. 27, 1910 534,313 Great Britain Mar. 4, 1941

